Users sometimes accidentally lose data in a file they are working on. Some losses occur because users change their mind about an edit they made, such as deciding they want to keep a paragraph that they deleted the previous day. Other losses occur because users inadvertently delete a portion of a file, such as by not realizing they hit the delete key while certain words were selected. Such accidental data loss is problematic for users, and unfortunately is oftentimes irreversible by the time the user realizes the data has been lost.